Effect of reef framework and bottom sediment on nutrient enrichment in a coral reef of the Gulf of Aqaba, Red Sea

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 239:277-285 (2002) - doi:10.3354/meps239277 Effect of reef framework and bottom sediment on nutrient enrichment in a coral reef of the Gulf of Aqaba, Red Sea Mohammed Rasheed1,2,*, Mohammad I. Badran2, Claudio Richter3, Markus Huettel1 1Max Planck Institute for Marine Microbiology, Celsiusstraße, 28359 Bremen, Germany 2Marine Science Station, University of Jordan and Yarmouk University, Aqaba, Jordan 3Centre for Tropical Marine Ecology ZMT, Fahrenheitstraße 6, 28359 Bremen, Germany *E-mail: my_rasheed@yahoo.com ABSTRACT: Inorganic nutrients and chlorophyll a concentrations were measured bi-weekly in a transect across a coral reef in the Gulf of Aqaba over a period of 1 yr. The nutrient and chlorophyll concentrations were compared to those in adjacent offshore waters (400 m depth). In reef and offshore waters, nutrient (ammonium, nitrite, nitrate, phosphate and silicate) and chlorophyll a data showed seasonal changes, with high concentrations in winter and low concentrations in summer. However, throughout the summer, nutrient concentrations in the coral reef waters significantly exceeded those in the offshore waters, while this difference was less pronounced in winter. This difference was caused by nutrient release from regenerative spaces in the reef framework and coral sand. In the reef framework water (i.e. cavity water), nutrient concentrations were 1.2- to 2.3-fold higher than those in the surrounding waters, corresponding to fluxes of 14.5 mmol m-2 d-1 for ammonium, 7.7 mmol m-2 d-1 for nitrate, 0.9 mmol m-2 d-1 for nitrite, and 1.3 mmol m-2 d-1 for phosphate. In the less permeable reef sediments, nutrient concentrations exceeded those of the free-stream waters by factors of 15 to 80. Here, the calculated diffusive fluxes were 0.06 mmol m-2 d-1 for ammonium, 0.03 mmol m-2 d-1 for nitrate, 0.01 mmol m-2 d-1 for nitrite, 0.01 mmol m-2 d-1 for phosphate, and 0.07 mmol m-2 d-1 for silicate. Our results highlight the importance of the reef framework and coral sand for the trapping and mineralization of particulate organic matter and the regeneration of nutrients in oligotrophic coral reef waters. KEY WORDS: Nutrients · Coral reef · Seasonality · Porewater · Reef framework · Coral sand Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 239. Online publication date: August 23, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.